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PostPosted: Tue Jun 20, 2017 6:42 pm 
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whew, finally
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Simple question, why is bearing preload so important on a pinion, yet in an axle wheel bearing it doesn't need any preload at all? Specifically the JK rear axle shafts have tapered roller bearings with zero preload, in fact they usually have around 10 thousands of axial play when assembled even brand new.

Yet the same type of bearing in a pinion needs a precise preload. Obviously it can't have axial play to keep the gears in good mesh, but if the preload is even a bit low the bearing goes bad and makes noises.

So why is it totally fine in an axle bearing, yet not in other applications, with the same type of bearing?


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PostPosted: Tue Jun 20, 2017 7:37 pm 
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That's a good question. The outputs on my transfer care also have like .005 of end play on the tapered bearings. I dont know the answer.

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PostPosted: Tue Jun 20, 2017 9:57 pm 
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My guess is the differential is a hypoid gear (pinion centerline offset from ring gear centerline) and sees enormous axial loads compared to the other examples.




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PostPosted: Wed Jun 21, 2017 4:41 am 
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This PDF explains the differences between pre-load and end play. In simple terms, when 2 tapered bearings are mounted to the same shaft, pre-load is the method used to properly set them. Where one bearing is used, end play is the proper method.

https://www.timken.com/wp-content/uploa ... hure-1.pdf

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